Tropical Weather Discussion

axpz20 knhc 182220

Tropical weather discussion
NWS National Hurricane Center Miami FL
2205 UTC Mon Feb 18 2019

Tropical weather discussion for the eastern Pacific Ocean from
the Equator to 32n, east of 140w. The following information is
based on satellite imagery, weather observations, radar, and
meteorological analysis.

Based on 1800 UTC surface analysis and satellite imagery through 
2000 UTC.

...Intertropical convergence zone/monsoon trough...

Climatologically, during portions of the months of March and 
April of each year, a double ITCZ develops across the eastern 
Pacific basin, with a convergence zone of clouds and convection 
on either side of the Equator. This pattern has developed in the 
past week, while no monsoon trough is present E of 140w. 

Currently, a weak surface trough is analyzed from northwestern 
Colombia to 04n82w to 04.5n99w to 02n111w. The ITCZ in the 
northern hemisphere extends from 02n112w to 00.5n130w to 
01.5n140w. Scattered moderate isolated strong convection is 
within 150 nm N of trough between 96w and 111w. 

An early season and well defined second ITCZ is noted S of the 
Equator and extends from 04s84w to 03.5s93w to 00.5s106w to 
02.5s122w. Scattered moderate to strong convection is within 
180 nm S of this ITCZ axis between 86w and 106w.


Offshore waters within 250 nm of Mexico...  

A cold front has entered the forecast area and extends from 
32n111w SW across the northern Gulf of California to 19.5n113.5w 
to 27n122w to 30n131w. Fresh to strong NW winds and seas of up 
to 13 ft in NW swell follow the front. The front is forecast to 
dissipate tonight as it moves southeastward across the northern 
Gulf of California and northern Baja California peninsula. A 
strong and persistent ridge continues to dominate the offshore 
forecast waters W of Baja California, and extends well beyond 
the revillagigedo islands to near 14n107w. The pressure gradient 
between the ridge and lower surface pressure over the SW of 
United States will support fresh to strong NW-N winds across the 
offshore waters W of Baja California through Tue morning with 
seas of 8 to 12 ft in NW swell, before winds and seas begin to 
diminish significantly Tue afternoon through early Thu. 

Gulf of california: a cold front is moving across the northern 
Gulf between 29n and 30n this afternoon. Fresh to strong 
westerly winds and seas of 5-7 ft are occurring just south of 
the front, while moderate to fresh NW winds are spilling into 
far N portions of the Gulf behind the front. As the front falls 
apart tonight, fresh northerly wind flow is expected to develop 
throughout most of the Gulf on Tue, diminishing to moderate to 
locally fresh Tue night through Wed. Seas will build to 4-6 ft 
by midday Tue across central and southern portions and then 
gradually diminish through Wed.

Offshore waters within 250 nm of Central America, Colombia, and 
within 750 nm of Ecuador...

Gulf of papagayo: fresh to strong winds are forecast across the
Gulf of papagayo most of the forecast period, but mainly during
the overnight and early morning hours with the assistance of the
nocturnal drainage flow, and some added enhancement from the 
easterly gradient flow from the SW Caribbean. Seas will build to 
around 8 ft Tue through Wed.

Gulf of panama: mainly gentle to moderate northerly winds are 
expected across the Gulf of Panama, with moderate to fresh winds 
at night tonight, and again Tue night, with seas of 3 to 5 ft.

Remainder of the area... 

A strong 1042 mb high pressure center, located well to the north-
northeast of the Hawaiian islands near 42n145w, will remain in 
this general location through Wed. The associated ridge axis 
extends southeastward across the northern forecast waters to 
well se of the revillagigedo islands to near 14n107w. The 
pressure difference between this ridge and broad low pressure 
lingering across the Hawaiian islands area is resulting in a 
tight pressure gradient across most of the area N of about 07n 
and W of 120w, where fresh to strong NE-E winds prevail, with 
seas in the range of 9 to 18 ft in N swell. The aerial extent of 
these winds will diminish over the next couple of days as the 
low pressure north of the Hawaiian islands moves westward. The 
area of fresh to strong northeast to east winds will persist, 
but mainly W of 130w. The seas there will slowly subside to 
around the 8 to 11 ft through the next 48 hours as the current 
large N swell moving through the area gradually exits se of the 



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